Assessing reservoir host status in leishmaniasis with special reference to the infectiousness of Leishmania (Viannia) braziliensis infections in wild rodents

ABSTRACT Molecular methods have been responsible for a notable increase in the detection of Leishmaniinae infections in wild animals. Determining their infectiousness is of paramount importance in evaluating their epidemiological significance. One of the most efficient ways of determining infectiousness for vector borne diseases is xenodiagnosis with the appropriate vector. However, this is logistically very difficult to accomplish in the field, and an ideal solution is to find a molecular surrogate for xenodiagnosis. In this review we discuss different approaches to the problem by focusing on the infectiousness of Leishmania (Viannia) braziliensis in rodents under laboratory and field conditions. Comparisons with similar studies for other Leishmania species emphasizes that there are pivotal differences in the infectiousness and the importance of asymptomatic infections in different hosts. Potentially the most promising surrogate is the real time quantitative PCR (qPCR). However, its success depends on choosing a tissue that relates to the vector's feeding location and the parasite's tissue tropism. This requires detailed knowledge of the infection of each species in its wild hosts. We conclude that for L. (V.) braziliensis infections in wild rodents the tissue of choice for a molecular xenodiagnostic test, based on the qPCR is blood, providing that a significant number of samples must be examined.

Should reproductively isolated populations of Lutzomyia longipalpis sensu lato receive taxonomically valid names?

A group of 18 research workers involved in different aspects of the biology of Lutzomyia longipalpis discussed whether or not it is important to give taxonomically valid names to populations that have been defined by biological, biochemical and molecular methods to be reproductively isolated. The type material of this medically important species has been lost and because of this it was recommended that a colony should be established from insects captured in the region of the type area and that their description should serve as the basis for future descriptions. It was pointed out that there is a lack of uniformity in the naming of closely related American sand flies and that some of the differences between populations of Lu. longipalpis are greater than those between accepted species. The majority of the participants agreed that the populations that have been defined in the literature as sibling species should be named.

Etiology of cutaneous leishmaniasis and anthropophilic vectors in Juruti, Pará State, Brazil / Etiologia da leishmaniose cutânea e vetores antropofílicos em Juruti, Estado do Pará, Brasil

In a preliminary study in Juruti, a mining municipality in western Pará State, Brazil, 12 out of 21 patients suspected of presenting cutaneous leishmaniasis showed positive PCR (SSUrDNA and G6PD): Leishmania (Viannia) braziliensis (9/12; 75 percent) and L. (V.) sp. (3/12; 25 percent). Entomological studies in the same location revealed the presence of 12 different phlebotomine species (n =105). One of the most common species was Lutzomyia (Psychodopygus) complexa (17 percent) which is both highly anthropophilic and a known vector of L. (V.) braziliensis in other regions of Pará. These preliminary findings should serve to guide future epidemiological surveillance in Juruti.

Em um estudo preliminar em Juruti, um município minerário na região oeste do Estado do Pará, Brasil, 12 de 21 pacientes suspeitos de possuírem leishmaniose cutânea tiveram PCRs positivas (SSUrDNA e G6PD): Leishmania (Viannia) braziliensis (9/12; 75 por cento) e Leishmania (Viannia) sp. (3/12; 25 por cento). Estudos entomológicos na mesma localidade revelaram a presença de 12 diferentes espécies de flebotomíneos (n = 105). Uma das espécies mais comuns foi Lutzomyia (Psychodopygus) complexa (17 por cento) que é altamente antropofílica e reconhecida vetora de L. (V.) braziliensis em outras regiões do Estado do Pará. Esses resultados preliminares servem como orientação para futura vigilância epidemiológica em Juruti.

The leishmaniases - survival and expansion in a changing world: a mini-review / x

The number of cases of visceral and cutaneous leishmaniasis is increasing globally at an alarming rate irrespective of the region and the leishmaniases are amongst the top emergent diseases in spite of control measures. In the present review attention is drawn to some of the reasons for this. The leishmaniases have expanded beyond their natural ecotopes due to the ecological chaos caused by man and this in turn affects the levels of his exposure to the vectors. Examples of how different phenomana (such as war, civilian migration, immuno-suppression caused by medication and viral infections, globalization of work and leisure and transmission outside endemic areas) contribute to the spread and increase of the disease are discussed.

Recent observations on the sand fly (Diptera: Psychodidae) fauna of the State of Rondônia, Western Amazônia, Brazil: the importance of Psychdopygus davisi as a vector of zoonotic cutaneous leishmaniasis

Sand flies were collected in the central region of the state of Rondônia (W 64 30' to 63 00' and S 10 00'to 11 00') using Shannon and CDC light traps from October 1997 to August 2000. A total of 85,850 specimens representing 78 named species were captured. Of these 14 were new records for Rondônia. The proportion of males/females was 1/1.131. Trypanosomatids, that are presently being identified, were detected in 11 species. Leishmania (Viannia) naiffi was recorded from Psychodopygus davisi and P. hirsutus. In the present study the dominant species was P. davisi (39.6 percent) followed by Lutzomyia whitmani (13.1 percent), P. carrerai (11.6 percent), and P. hirsutus (10.2 percent). The importance of P. davisi as a vector of zoonotic cutaneous leishmaniasis is discussed

Infecção experimental em Biophalaria straminea (Dunker 1848) pigmentado e albino com Schistosoma mansoni, prcedente de área endêmica em Belém, Pará, Brasil / Experimental infection of pigmented and albino Biomphalaria straminea strains with Schistosoma mansoni (Dunker 1848), from endemic area in Belém, Pará, Brazil

Introdução: A dispersão do Biomphalaria straminea pigmentado em Belém, Pa. foi assinalado por Costa (1952). O encontro e estudo do Biomphalaria straminea variedade albina, nesta mesma área de transmissão, não tem registro bibliográfico. Objetivo: Estudar a suscetibilidade das variedades pigmentado e albino de B. straminea, colonizados em laboratório e infectá-las com cepa de Schistosoma mansoni isolada da mesma área e com adaptação prévia em laboratório.Método: Realizadas infecções em85 espécimes de B.straminea pigmentados, os quais foram expostos a 8 miracídios. O mesmo procedimento foi usado em 200 espécimes de B.straminea albina, expostos a 10 miracídios e depois observados durante 80 dias. Para o grupo controle foram utilizados B.glabrata coletados na área e colonizados previamente em laboratório. Resultados: Os caramujos B.straminea pigmentados mostram-se suscetíveis para uma cepa de S.mansoni. Por outro lado, a variedade albina, mostrou-se refratária a esta cepa e, também, para outra, esta isolada de paciente de outro Estado, ambas utilizadas nos testes. Conclusão: Com esse resultado, podemos concluir que os criadouros habitados por B.straminea variedade albina não constituirão perigode transmissão de esquistossomose nos bairros do Telégrafo e Sacramenta na cidade de Belém, Pará

Observaçöes sobre o diagnóstico laboratorial e a epidemiologia da leishmaniose tegumentar no Estado do Paraná, sul do Brasil / Observations on laboratory diagnosis and cutaneous leishmaniasis epidemiology in the State of Paraná, sul of Brazil

De 1986 a 1997 foram encaminhados ao Laboratório de Ensino e Pesquisa em Análises Clínicas, da Universidade Estadual de Maringá, 1418 pacientes suspeitos de leishmaniose tegumentar para diagnóstico laboratorial. Os testes utilizados foram a intradermorreaçäo de Montenegro, reaçäo de Imunofluorescência indireta, pesquisa direta, isolamento e identificaçäo de Leishmania. Destes pacientes, 955 (67,30 por cento) apresentaram pelo menos um dos testes positivo, entre os quais 804 (84,20 por cento) contraíram a infecçäo no Estado do Paraná, 665 (69,6 por cento) tinham de 15 a 49 anos de idade, 658 (68,9 por cento) eram do sexo masculino, 523 (54,8 por cento) foram diagnosticados nos 3 primeiros meses de evoluçäo da lesäo e 74 (7,7 por cento) apresentavam comprometimento nasobucofaríngeo. Dos 83 municípios do Estado do Paraná envolvidos, destacaram-se Säo Jorge do Ivaí (10,2 por cento), Doutor Camargo (9,80 por cento), Terra Boa (7,3 por cento), Maringá (7,3 por cento), Jussara (6,0 por cento) e Cianorte (4,5 por cento). Foram isoladas 77 cepas de Leishmania (Viannia) braziliensis, predominando (63,6 por cento) o serodema 1

Teste de aglutinaçäo directa no sorodiagnóstico da leishmaniose visceral no estado do Pará / Direct agglutination test in the serodiagnosis of human visceral leishmaniases in the State of Pará, Brazil

The direct agglutination test (DAT) was evaluated for serodiagnosis of visceral leishmaniasis (VL) in human and canids (dogs and foxes Cerdocyon thous). The results were compared with those of the immunofluorescent antibody assay (IFAT) and enzyme-linked immunosorbent assay (ELISA). The sera used were from: humans (303): confirmed VL (16), suspected VL (65), other conditions (102), negative controls (15) and individuals from an endemic area (105); dogs (82): from an endemic area (68), Salvaterra/Marajó/Pará (21 of which were parasitologically positive), and negative controls (14), from Belém; foxes (9): caught on Marajó Island. Antigens for DAT were prepared from promastigots of L. (L.) donovani, L. (L.) chagasi. Antigens used in ELISA and IFAT were prepared from promastigotes (soluble antigen) and amastigotes respectively of L. (L.) chagasi. In humans, the specificity and sensitivity of DAT using L. (L.) donovani were high (98.4 per cent and 100 per cent respectively) and comparable to that of IFAT (97.5 per cent and 100 per cent). ELISA was less specific (84.8 per cent) although similarly sensitive (100 per cent). In dogs, DAT was more specific using L. (L.) donovani as antigen than using L. (L.) chagasi. However, both DAT and ELISA were less sensitive (both 71.4 per cent) than IFAT (100 per cent). This difference was reflected in the results from endemic dogs, 87 per centof which were positive by IFAT but only 54 per cent by ELISA and 49 per cent by DAT. Similarly, all 9 fox sera were positive by IFAT, 7 of 9 (78 per cent) by ELISA but none by DAT. In conclusion, DAT using L. (L.) donovani antigen can provide a useful test for human VL; utilization on a large scale would be possible with a suitable reference laboratory to monitor antigen quality. However, DAT appears less useful for canine studies, as it was less sensitive than ELISA and especially IFAT in detecting canine infection.

Taxonomy of the genus Leishmania: present and future trends and their implications

The application of different taxonomic methods (Cladistic, Evolutionary Taxonomy and Numerical Taxonomy) to the taxonomy of the Genus Leishmania are reviewed. The major groupings of the most recent classifications obtained using the cladistical approach agree with the major divisions of previous classifications which used traditional taxonomy (Evolutionary Taxonomy). The advantage of the cladistical approach is that it produces cladograms whose branches indicate more accurately levels of relationships between the different taxa. Numerical Taxonomy is useful for identification but not as good as the cladistical approach for classification. The ancient division of this monophyletic genus into two major evolutionary lines supports the use of the subgeneric names Leishmania and Viannia.

Nota sobre leishmaniose canina no noroeste do Estado do Paraná, sul do Brasil / Leishmaniasis in dogs in southern Brazil

Em área endêmica de leishmaniose tegumentar americana no Município de Jussara, Estado do Paraná, Brasil, detectaram-se três cäes domésticos infectados por Leishmania (Viannia) brasiliensis

A brief history of the genus Leishmania (Protozoa: Kinetoplastida) in the Americas with particular reference to Amazonian Brazil

First recognized as a cause of human disease, the genus Leishmania (Protozoa: Kinetoplastida: Trypanosomatidae) has been found to include numerous species infecting a wide variety of mammals, among which the parasites are transmitted by many different species of blood-sucking phlebotomine sandflies (Diptera: Psychodidae: Phlebotominae). Transmission is not thought to be a haphazard affair, however, but to involve relatively specific mammal/sandfly combinations, dictated by environmental and other barriers. Major events in the history of Leishmania and leishmaniasis in the Americas are reviewed, with particular emphasis placed on ecology, taxonomy, and the role of some parasites as pathogens of man. The neotropical leishmanias were probably all sylvatic in origin and, by virtue of its unusually rich and varied fauna, Amazonia is rich, too, in Leishmania species.

Leishmaniose cutânea experimental: III. Aspectos histopatológicos do comportamento evolutivo da lesäo cutânea produzida em Cebus apella (Primates: Cebidae) por Leishmania (Viannia) lainsoni, L. (V.) brasiliensis e L. (Leishmania) amazonensis / Experimental cutaneous leishmaniasis: III. Histophatological aspects of the evolutive behavior of the cutaneous lesion induced in Cebus apella (Primates: Cebidae) by Leishmania (Viannia) lainsoni, L. (V.) braziliensis and L. (Leishmania) amazonensis

Estudaram-se os aspectos histopatológicos relativos à evoluçäo da infecçäo experimental produzida em Cebus apella (Primates: Cebidae) por Leishmania (V.) lainsoni, L. (V.) braziliensis e L. (L.) amazonensis. O exame microscópico de biópsias seqüênciais, obtidas dos animais a intervalos definidos d etempo (a primeira, âs 48 ou 72 horas após a inoculaçäo, e as seguintes, a cada 30 dias), mostrou que o desenvolvimento das lesöes, independente da espécie de Leishmania inoculada, pass por uma seqüência de etapas a nível tecidual - 1) infiltrado inespecífico crônico; 2) nódulo macrofágico (com numerosos parasitas); 3) necrose das células parasitadas; 4) granuloma epitelióide; 5) absorçäo da área necrosada (às vezes formando granuloma de corpo estranho); 6) infiltrado inespecífico crônico residual); e 7) cicatrizaçäo - que representaria a formaçäo e a resoluçäo das lesöes. Discutiram-se também os prováveis mecanismso imunopatológicos que determinaram esta seqüência de eventos e sua possível semelhança com a evoluçäo das lesöes na leishmaniose tegumentar humana

Eimeria vitellini n. sp. (Apicomplexa: eimeriidae) from the brazilian toucan Rhamphastos vitellinus vitellinus Lichtenstein (Aves: Picicformes: Rhamplastidae)

Eimeria vitellini n. sp. is described from the faeces of the Rhamphastos v. vitellinus. Oocysts broadly ellipsoidal to oval (egg-shaped), 22,6 x 18.3 (20.0-25.0 x 16.3-22.5) micronm, shapeindex (length/width) 1.2 (1.1-1.1). Oocyst wall a single colourless layer about 0.5 micronm thick, becoming thinner at one ectremity, at which point the oocyst usually ruptures. No oocyst residuum, but 1 or 2 small polr bodies of about 1.0-1.5 x 0.5-1.0 micronm. Sporocysts ellongated ellipsoid (pearshaped), 14.3 x 7.5 (13.8-15.0 x 6.9-7.5) micronm, shape-index (1.9 (1.8-2.0), with a thin colourless wall bearing a very delicate Stieda body: a conspicuous sub-Stieda body is present. Sporozoites with anterior and posterior regractile bodies and strongly recurved around a bulky, compact sporocyst residuum composed of relatively fine granules and spherules